Medicines in the form of pills, capsules, tablets and the like are generally packaged in blister packs. A blister pack usually comprises a generally quadrangular tray with a set of pockets or bubble housings into which the pills or the like are inserted. The bubble housings, or pockets, are sealed with a sealing film, typically made of aluminium or paper, stretched over the tray and bonded thereto. Alternatively, the pills can be enclosed in compartments created between two flexible films bonded together.
As is known, blister packs provide a convenient packaging solution for those who use medicines occasionally, but are much less suitable for use in a hospital environment, where it is preferable for medicines to be stored separately in single doses, to allow more precise and regular distribution in the various wards according to the dosage regime for each patient.
The advent of automatic medicine management systems in the hospital environment has made it necessary to provide a mechanism for automatically separating the single doses grouped in blister packs from one another.
There are known separator devices suitable for this purpose, for example the device described in European Patent EP 1 560 756 held by the present applicant, in which two pairs of blades cut the blister pack along predetermined straight lines so as to separate the pockets of the blister pack, each containing a unit dose of medicine, from one another, while keeping each medicine sealed in its pocket. Although the device disclosed in this European Patent has proved effective in numerous applications, it is not suitable for use with certain types of blister packs; this is because, in 40-60% of cases, the pockets are arranged in a complex layout which prevents separation by means of this device.
In order to overcome this drawback, the applicant has developed a further separator device, disclosed in International Patent Application WO 2012/020354. This separator device uses an ultrasonic cutting head to cut the blister packs along paths predetermined according to cutting schemes, including complex schemes, associated with each different type of blister pack. In the use of this separator device, a blister pack is positioned on a bearing surface, from which, for example, the ultrasonic cutting head projects, in a predetermined reference position which is defined, for example, by a stop such as a projecting edge of the bearing surface, which is located at one of the corners of the surface and is therefore L-shaped. From this predetermined reference position, the blister pack is then moved on the bearing surface in a series of predetermined movements which define the cutting of the blister pack by the ultrasonic cutting head.
The separator device disclosed by WO 2012/020354 can be used for the effective separation of a certain number of types of blister pack, having layouts which may be rather complex. However, there are some types of blister packs in which the pockets containing the products to be separated are very close to one another, and for these packs the cutting must be carried out with very high precision to avoid nicking a pocket and thus compromising the sterility of the medicine contained in it. Even where it is possible to achieve such high precision with the prior art separator devices, particularly close manufacturing tolerances and constant monitoring of the mechanical play are required, resulting in a high cost for the manufacture of the separator device and for its continuous use and periodic maintenance.
In greater detail, the applicant has discovered that, in blister packs of a single medicament produced by a given pharmaceutical firm, the distance of the pockets from the edge of the blister pack is subject to a degree of variability, although the pockets are always in the same specific relative arrangement and at the same distance from one another. In the case of blister packs with very closely spaced pockets, in which the distance from one pocket to another may be less than 2 mm, this lack of precision in the distance between the blister pack edge and the pockets, although small in absolute terms, may be sufficient to compromise the integrity of one or more pockets during the cutting of the blister pack, especially given that the blade typically has a thickness of about 0.65 mm, which is significant relative to the distance between two adjacent pockets.